Scientists at the University of Washington have made the first-ever accurate determination of a solid-state “triple point” in a substance called vanadium dioxide. The material is known for switching rapidly – in as little as one 10-trillionth of a second – from an electrical insulator to a conductor, and thus could be useful in various technologies.

In the context of water, a triple point is where its three phases – ice, liquid and vapor – can exist stably together, which happens only at a particular temperature and pressure.

“These solid-state triple points are fiendishly difficult to study, essentially because the different shapes of the solid phases makes it hard for them to match up happily at their interfaces,” said David Cobden, a University of Washington physics professor.